Hopefully a quick question.
I read the below wiki post on changing the PWM frequency.
Why would a frequency below 9kHz be desirable?
As I understand it, the setup around 9kHz generates the least PWM noise.
Any insights?
Boy, long time - no one asnwered. Yes, of course it's possible. I got more advanced versions, but based on STAR - got lots of blinkies as options.
No, think he means 9 kHz is too low, higher rates are desirable and possible. I use phase mode on the Tiny25 and Tiny85 at about 15.6 kHz, and I beleive my 13A code uses 18 .8 kHz in FAST mode.
Efficiency, lower and more stable moon mode.
High PWM frequency is OK for FET drivers. 7135 chips, on the other hand, are relatively slow and require a minimum PWM pulse width to fully turn on. This is why you may see discussions around using minimum 5-6/255 PWM duty cycle, and the sensitivity of this number related to the exact hardware in use (cell voltage, emitter type, driver, etc).
Against BLF wisdom I use 2.4 kHz PWM with FET+1 drivers. I do not PWM the FET though, only the 7135. No audible whine, and no visible (to me) PWM. Nice low moon mode. FET is used only for full-on turbo mode.
You could try 18.8 kHz PWM for the FET (MCU clock at 9.6 MHz, phase-correct PWM) and switch to a PWM divider of 8 (2.4 kHz PWM) when only the 7135 is in use. That should give the best of both worlds.
PWM frequency is something which depends a lot on personal taste.
Some people can’t stand anything in human hearing range, since the pulses make noise. So, nothing below 16kHz or 18kHz or whatever the top of their hearing provides.
Some people (like me) can’t stand anything with visible pulses, and sensitivity to that varies a lot per person. Like, I can see 8 kHz or slower PWM pretty easily, and anything under 2 kHz looks like a strobe light to me.
Some people prefer to focus on efficiency and stability instead, which slower pulses are better at. Slower pulses work on more hardware and provide more consistent output with higher efficiency. So, those are some pretty good reasons to slow it down as far as you can tolerate.
… and some people (mostly cheap light companies) just go for whatever is cheapest, which is usually super slow.
In general, the most useful range is from about 1 kHz to 20 kHz. Slower than that, and almost everyone can see the pulses. Faster than that, it loses more and more efficiency without any real benefit. I prefer the 16 to 20 kHz range.
Thanks everyone for the input.
Looking at the versions of this code I’m wondering if the Momentary version is intended to be used with a tactile switch (as opposed to clicky). The dev notes say it’s intended to be used with a “single momentary switch” but I’m not sure what that actually is.
Maybe I’m dreaming but I’m hoping I can find a tactile switch mounted to a 17mm or 20mm PCB to use with this firmware and a 105c.
Thoughts?
Thanks in advance.
"single Momentary switch" means electronic switch - wired up to a pin of the MCU, for how they use the wording. A tactile switch is still a power switch, just like a clicky.
If you have a flashlight that is an e-switch with a driver mounted switch, our standard way of mod upgrading is to piggyback on a driver with true e-switch support. We usually use pin #2 of the MCU as the switch input, instead of the OTC, and figure out a way to wire up a jumper from the driver mounted switch. Also we usually strip off all parts, accept the switch, from the stock driver. I've ton a ton of them, many different types and sizes.
If you want to convert an e-switch to a tactile switch, oh boy... Dunno - the mounting and supporting the deeper throw of a mechanical switch may be a challenge, but probably has been done and posted about somewhere...
My attempt to search out an e-switch has been hindered by the fact that E-switch is also a company.
Here’s what I’m after: the ability to use a tactile switch with a 105C running the STAR firmware. The physical nature of it I can handle by machining something in a pinch, it’s the firmware aspect that I’m trying to get a handle on.
I was under the impression (based on who knows what) that this would require a MCU different than the ATTiny13a. I thought a clicky switch operated differently then a tactile switch in that a clicky physically opens and closes the circuit where as a tactile would “tell” the driver to turn on, off, etc.
Is it possible to use STAR, a 105c, and a tactile switch together?
The way you are describing a “tactile” switch is actually describing an E-switch. A tactile switch is a type of clicky switch. A tactile switch is the same as a Forward clicky as aposed to reverse clicky. The difference is that a forward clicky makes contact with power prior to latching/clicking. A reverse clicky clicks and then makes contact to power. Usually firmware is interchangeable for these two types of clicky switches. One requires you to select your mode level prior to clicking and the reverse clicky alows you to change modes after clicking and while the flashlight is latched on.
If you want an Eswitch, which is what you are describing, then you need a different firmware. Not a different mcu, just firmware. So, the 105c can be used with any of these switches depending on the firmware.
I think 
That’s the way I originally understood it as well.
For the sake of clarity by tactile switch I mean a switch like this: http://www.digikey.com/product-detail/en/e-switch/TL3340AF160QG/EG4627CT-ND/1885974
Ahhh… Tactile, not tactical… Ok well that is a momentary e-switch. You can use it with the 105c attached to pin 2 of the mcu or star 4. However, you need a momentary firmware. A 105c flashed for use with a clicky will need to be reflashed.
Ah ha!
Was mighty confused there for a bit.
So, I should be able to use STAR momentary with a 105C and a momentary e-switch.
Is anyone aware of a source of e-switches mounted to 17, 20mm, etc. PCBs?
I am unaware but someone may know of something. It’s usually a self job. I’ve used driver boards from cheap eBay lights I’ve had laying around. I strip it of all components and attach the switch then pot it together with my driver of choice.
Makes sense.
Was hoping for something like this with or without the spring but using an e-switch instead of a clicky.
I think the reason they are unavailable is because each lights Eswitch lines up in a different place with many sizes for hole diameter. It would be impossible to make a generic Eswitch board that would fit many lights.
When using a regular clicky switch with these drivers, all of the current flows through the switch.
When using an e-switch in the configuration we’ve been discussing would the current not flow through the switch?
I ask because I’m looking at switches on Digikey and none of them appear to have the necessary current rating.
Just wanted to double check.
No the curent wouldn’t flow through the eswitch. Because of that you can use very small switches and thin cables for the eswitch
+1 w/finges. I use 26 AWG or 30 AWG silicone. The two connections are from ground (BATT-) and usually pin #2 of the ATMEL MCU.
Very helpful. Because I’m a bit dense, it would be wired as below:
Ground~~switch~~>pin #2 of the MCU
Thanks